Improvement



PATENT OFFICE.

HENRY'DAvIEs, OF PORTSMOUTH, OHIO.

IMPROVEMENT IN BALANCED SLIDE-VALVES.

Specification forming part of Letters Patent No. 4i 1,909, dated March l5, 1864.

section of a valve-chest and valve and the mechanism for balancing the valve. Fig. 2 is a transverse vertical section ofthe same. Fi g.

3 is a plan of the same, with the balancingdiaphragm and its cover removed. Fig. 4 is a top view of the two levers H H, which are also shown in Fig. 1.

Similar letters of reference indicate corre sponding parts in the several figures.

This invention relates to a mode of balanc ing the valve.

The invention consists inl a novel mode of applying a flexible diaphragm in combination with a slide-valve, whereby the pressure of steam on the diaphragm is made to counteract that of the valve, and the valve is enabled to work with the least possible amount of friction upon its seat.

To enable others skilled in the art to make and use my invention, I will proceed to describe its construction and operation.

A, Figs. 1 and 2, is the slide-valve; B, the valve chest, and athe seat. The valve is ot'ordinary construction, except that it has the lap on the inside, for the reason that the steam is admitted below instead of above it. The ports b, b', andcare arranged in the seat in the usual manner, but the middle port, c, instead of beingtheexit-port, is the inlet-port andconnected with the induction-pipe I. The eductionpipe E is connected with the valve-chest. V

On the back of the valve-chest there is a hollow column, C, the interior of which is open to the valve-chest; and on the top of this column is the flexible diaphragm D, of sheet-copper or other suitable metal, coveredby a hollow steam-tight cap, C', which is bolted to a flange formed round the top of the hol low column, and thus made to secure the margin ofthe diaphragm in such manner as to make a perfectly steam-tight joint above and below it.

F is a rockerbar, having a bearing in the back of the valve at d, and having its upper end in the .form of an arc concentric with the bearing d.

Gr is what I call a fulcrum-bar,.arranged across, but loosely within, the column C, and having its lower surface straight and parallel with the valve seat. This bar rests on the arcformed top of the rocker-bar, and has in the center of its lower surface a notch or mortise for the reception of a tooth, e, like one ofthe teeth of a spur-gear, formed upon or secured in the top of the rocker at the middle of the arc, the said notch or mortise being of suitable form for the tooth to work in without any motion.

On the top of the fulcrum-bar, at equal distances from the center of its length, there are formed two V-shaped or knife edges, fv f, which form bearings for two levers, H H, which are arranged over the said bar, and the outer ends of which are made with V-shaped or knife edges g g, to bear against the upper surface of a groove, lL, which is formed around the interior of the column G. The inner ends of the said levers are fitted into each other with one or more tongues and grooves, as shown at i t' in Figs. 1, 2, and 4. J is a stud, secured steaintight in the center of the diaphragm D, having a V-shaped or knife edge, which bears across the inner ends of the two levers.

K is a small steam pipe, to admit steam from the induction-pipe I into the chamber m, which is formed within the cap C above the diaphragm.

L L are a series of sector-shaped or radial bars. The outer ends are made with V-shaped or knife edges jj, to rest upon the bottom of a recess, k, formed around the interior of the column (l below the diaphragm, and the inner ends of which rest on a shoulder, l, formed around the stud J, and are thus held up close under the dia-phragm.

The operation is as followsrThe valve is moved in the usual manner. When it is moved to the right, the steam from the part c enters at the right-hand end of the cylinder through the part b', and is exhausted from the lefthand end through b into the steam-chest and through the pipe E, and when it is moved to the left the steam enters at the left-hand end of the cylinder through b, and is exhausted at the right-hand through b into the steam-chest and through the pipe E. The exhaust-steam fills the column C, as well as the steam-chest. In the movementof the valve the rocker rolls against the under surface of' the bar G. The

steam enteringat o,be1ow the valve, tends tol i rocker F to the back of the valve, the area of the diaphragm being just sufficient for the downward pressure upon it to counteract the upward pressure upon the valve. In the movemeutof the valve the rocker gives no motion to the bar G, which, with all the parts above it, are stationary, except what slight movement is due to expansion and contraction by variations of temperature and to the wear of the parts.

Instead of the diaphragm D and radial bars L L, a piston may be substituted, but the diaphragm is preferable, as it Works without friction; and instead of the levers' H H some other means may be used to keep the under face of the bar G parallel with the valve-seat.

What I claim as my invention, and desire to secure by Letters Patent, is-

The rocker F, bar G, levers H H, stud J, diaphragm D, and radial bars L L, applied and operating in combination with aval ve, A, having the induction of steam under its face, substantially as herein specified.

, HENRY DAVIES. Witnesses:

loaNnLrUs MoGov, JOHN FEsKER, 

